Earth moving and screening equipment

ABSTRACT

A screen for use on buckets of earth moving equipment such as tractors, loaders and the like which is mounted to a generally Ushaped frame that is pivotable independently of the bucket about a horizontal axis between an operative position in which the screen is disposed beneath the bucket into an inoperative position in which the screen is disposed above the bucket. Power means move the screen between its operative positions and the frame fully stradles the bucket so that the bucket can be used for conventional earth moving and loading operations by placing the screen into its inoperative position. To screen the material the screen is placed beneath the bucket so that material dumped from the bucket must fall onto the screen.

United States Patent [1 1 Evers et al.

[54] EARTH MOVING AND SCREENING EQUIPMENT [75] Inventors: John J. Evers; Ralph E. Jones; Alvie E. Boyce, all of Tahoe City, Calif. [73] Assignee: Robert C. Gebhardt Co., Tahoe City, Calif.

[22] Filed: July 9, 1970 [21] Appl. No.2 53,603

[52] US. Cl ..209/421, 37/117.5 [51] Int. Cl. ..B07b 1/28 [58] Field of Search ..209/413, 418-421; 171/111, 132; 37/117.5, 118; 74/53, 107

[56] References Cited UNITED STATES PATENTS 3,461,968 8/1969 Longley ..37/117.5 X 3,080,983 3/1963 Blatt ..74/107 X o r 28 36 c o 34 0 45 May 15, 1973 Primary Examiner-Frank W. Lutter Assistant Examiner-William Cuchlinski, J r. Attorney-Townsend and Townsend [57] ABSTRACT bucket so that the bucket can be used for conventional earth moving and loading operations by placing the screen into its inoperative position. To screen the material the screen is placed beneath the bucket so that material dumped from the bucket must fall onto the screen.

12 Claims, 11 Drawing Figures PAHZNTED MAY] 51975 SHEET 3 BF 4 NES ALVIE E. BOYCE ATTORNEYS PATENTEUMAY 15 I975 SHEET Q 0F 4 FIGJI INVENTOR. JOHN J. EVERS RALPH E. JONES BY ALVIE E. BOYCE AT TORN EYS 1 EARTH MOVING AND SCREENING EQUIPMENT BACKGROUND OF THE INVENTION Many construction projects require the use of relatively fine earth, that is screened earth from which larger rocks and debris have been removed. For example, when laying pipe lines for sewer installations or the like a trench is dug into which the pipe is laid. The trench is filled with screened ground or sand. Ideally, the ground removed from the trench is replaced therein. However, in instances where the ground has large rock inclusions, as is frequently the case, the removed ground cannot be used without being first screened.

Such screening has heretofore been relatively expensive since the removed ground must be picked-up, as with a loader, and discharged onto a screen. Thereafter, the screened material must again be picked-up from beneath the screen and transported to the trench for placement therein. Thus, extensive handling of the material and its transport over various distances to the screen and to the trench is necessary. This is time consuming, slow and substantially increases already high construction costs.

As a result thereof it is frequently more economical to haul screened ground from a remote quarry or the like for direct placement into the trench. The tie-up of relatively expensive screening machines and the time consuming handling of the ground is thereby eliminated. Nevertheless, the cost of filling the trench with screened material remains high. For example, in the Lake Tahoe basin in the Sierra Nevada of California, screened ground is frequently trucked in from outside the basin for filling sewer pipe trenches and the like at a cost of between $3.00 to $5.00 per cubic yard. Considering the need for up to several thousand cubic yards of screened material for a single, medium sized construction project the expense of such material is substantial.

An aesthetically and ecologically highly undesirable by-product of such construction practices is that the originally trenched-out material forms an unsightly mound running along the trench. During dry weather the mound is the source of dust and in the rainy season it substantially contributes to the run-off of silt and the resulting contamination of rivers and lakes. The removal of the mound requires additional machinery and labor and thus increases construction costs. Furthermore, since the removed material must be dumped it merely transfers the unsightly appearance and pollution caused by the mound to another locale.

SUMMARY OF THE INVENTION The present invention provides a screen that is mounted to earth moving or loading vehicles and which is so constructed and positioned that it can be alternatively positioned in an operative position beneath a bucket of the vehicle and in an operative position above the bucket. While in the operative position, material such as trenched-out ground dumped from the bucket falls onto the screen. Fine material passes the screen while coarse material, rocks and the like is retained on the screen for subsequent discharge therefrom. When the screen is placed in its inoperative position, the bucket can be used in av conventional manner for the pickup of materials such as ground or rocks, their transfer to the point of use and the dumping of the materials in the bucket for the loading of transport vehicles or for any other desired purpose.

In its broadest aspect, the screen of the present invention comprises a frame member supporting the screen and pivot means movably connecting the frame member to a support structure and permitting placement of the screen beneath container means carried by the support structure in a substantially horizontal operative position. Power driven means are provided for pivoting the frame member about a substantially horizontal axis defined by the pivot means into an inoperative position through an arc of substantially more than about to provide clear access to the container in a substantially horizontal direction to facilitate the filling of the container and for discharging screenedout matter from the screen.

In the preferred embodiment of the invention, the mounting means comprises a generally U-shaped frame having upwardly extending legs that are keyed to a horizontally disposed shaft journaled in suitable bearings of a bucket defining the container means. The power drive means comprises a hydraulic actuator, a suitable hydraulic motor, or conventional motor means imparting rotational motion through an arc of up to about and the necessary torque to the shaft so that the screen can be moved from a lowermost, operative position into an upwardly extending inoperative position to provide complete access to the bucket and to further prevent an impairment of the operators sight.

The screen of the present invention is a relatively inexpensive attachment for tractors, loaders andthe like when compared to the cost of independent prior art screening machines. It is attached. to the vehicle and is thus ready for use wherever the vehicle is located. Long trips of the vehicle from a pickup point to a screen and back are thereby eliminated.

In the previously referred to example of filling pipe line trenches with screened material, the invention enables a conventional pickup of the t'renched-out material and merely requires movement of the material holding bucket to vertically above the trench, usually a distance of no more than a few feet. When in that position, the screen is lowered into its operative position and the material in the bucket is discharged onto the screen. Only screened material can enter the trench while large rocks and debris are retained on the screen. After the bucket has been emptied, the screen is rotated into it inoperative position. Rocks and the like not passing the screen are thereby automatically discharged-from the screen. This operation is repeated until the trench is filled.

The trucking in of screened material to the construction site to lower high prior art screening costs is no longer necessary. An 18 to 20 ton wheel bucket loader provided with a screen constructed in accordance with the invention can pickup and screen up to about 500 cubic yards or more per day at a total cost of no more than about $400.00 a cost of less than $1.00 per screened cubic yard. Thus, the construction cost reduction made possible by the present invention can amount to several thousand dollars for a single construction project of only modest size.

Aside from the economics provided by the present invention, the objectionable aesthetic and ecological 3 side effects resulting from the replacement of the trenched-out material with trucked-in, screened ground is eliminated. The construction site is clear of excess ground and remains substantially in its natural state while air and water pollution from dust and excess silt run-off is virtually eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a wheel loader provided with screen constructed and installed in accordance with the present invention and illustrates the screen in its operative position;

FIG. 2 is a view similar to FIG. 1 but illustrates the screen in its inoperative position for the pickup of material with a bucket of the loader;

FIG. 3 is a front elevational view of the vehicle;

FIG. 4 is a fragmentary, enlarged front elevational view illustrating a portion of frame to which a vibratory screen is mounted;

FIG. 5 is an enlarged, fragmentary rear elevational view illustrating one-half of the bucket and a power drive for movement of the screen between its operative and inoperative positions;

FIG. 6 is an enlarged, fragmentary side elevational view taken on line 6-6 of FIG. 5 and illustrates the mounting of the screen supporting frame;

FIG. 7 is an enlarged, fragmentary cross sectional side elevational view through the bucket and illustrates the power drive means in a position in which the screen is in the inoperative position;

FIG. 8 is a side elevational view similar to FIG. 7 and illustrates the position of the power drive means wherein the bucket is in its operative position;

FIG. 9 is a plan view of a two part bucket and illustrates a large mesh bucket screen preventing large rocks and the like from dropping onto the vibratory screen;

FIG. 10 is a side elevational view taken along line 1010 of FIG. 9 but shows the bucket in its opened position; and

FIG. 11 is a fragmentary side elevational view of a bucket provided with vibratory screen constructed in accordance with the invention and power driven with a hydraulic motor.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 through 4, a wheel-type loader 16 generally comprises a vehicle 18 with a frame 20, an engine 22 mounted thereon and power driven wheels 24 which propel the vehicle over the ground. A bucket 26 is pivotally mounted to a vertically raisable arm 28 secured to vehicle frame 20. A tilt mechanism 30 is mounted to the arm end connected to the bucket for pivoting the bucket about horizontal pivot pins (not separately shown) that connect the bucket to the free end of arms 28. Thus, the bucket can be raised and pivoted into a material holding position, as illustrated in FIG. 1, or lowered and tilted in a counterclockwise direction for the pickup of material such as ground 32 and as illustrated in FIG. 2.

The bucket may be of any one of several readily available constructions. The one illustrated comprises an aft or shell portion 34 which is pivotally secured to arms 28 and a forward or clam portion 36 which is in turn pivotally secured to the shell portion by pivot pins 38. A hydraulic actuator (not shown in FIGS. 1 through 4) is provided for opening and closing the two portions of bucket 26 for the discharge of material in the bucket between a gap formed by the two bucket portions.

A U-shaped frame 40 is defined by a pair of laterally spaced upright legs 42 disposed adjacent each side of bucket 26 and a generally horizontal, rectangular frame 44 interconnecting lower ends 46 of the legs. A vibratory screen 48 is mounted to rectangular frame 44 with a plurality of spring blades 50 permitting vibratory motions of the screen independent of U-frame 40. A vibrator 52 is mounted to rectangular frame 44 and connected to screen 48 to provide the necessary vibratory energy.

An upper end 54 of legs 42 is connected to pivot pins 38 and power driven means (not shown in FIGS. 1 through 4) is provided to pivot U-shaped frame 40 and screen 48, hereinafter referred to as screening unit 49, about the axis of pivot pin 38 between a lower, operating position of the screening unit (illustrated in FIG. 1) and an upper, inoperative position of the screening unit (illustrated in FIG. 2).

To screen earth, rocks and the like through vibratory screen 48 the power drive means is actuated to pivot the screening unit into its inoperative position. Arms 28 mounting bucket 26 are lowered and tilt mechanism 30 is actuated to pivot the bucket in a clockwise direction, as viewed in FIG. 2, to place the cutting edge 56 of the bucket defined by a plurality of teeth 58 adjacent to the ground. The vehicle is now driven forward until the bucket digs into the earth. Thereafter, the bucket is tilted in a clockwise direction and arms 28 are raised until the two are in about the position illustrated in FIG. 1. The power drive means for the screening unit 49 is now energized to pivot the unit about pins 38 in a counterclockwise direction until the screening unit is at its lowermost, operating position. Vibrator 52 is energized and bucket portions 34 and 36 are opened to dump material in the bucket onto the screen. Fine material falls through the screen and past rectangular frame 44 onto the ground. Coarse material such as rocks, roots or branches and the like remain on the screen.

After the bucket has been emptied, the power drive means for screening unit 49 is energized to pivot it in a clockwise direction, as viewed in FIG. I, back into its inoperative position. Thereafter, the above described steps for filling bucket 26 with ground are repeated. It will be noted that upon return of the screening unit into its inoperative position material which could not pass through screen 48 is automatically discharged from the unit and falls to the ground where it can be subsequently collected. Alternatively, the bucket can be positioned so that screened-out material on screening unit 49 drops into the bucket for subsequent discharge at a suitable location.

To assure that all material dumped from bucket 26 during the screening operation is deposited on screen 48 a deflector blade 60, preferably constructed of a resilient material such as relatively thick, reinforced rubber or plastic sheet is mounted to sides of legs 42 facing the screen. The deflector blade is preferably secured to a sloping leg 62 of an'open angle 64 that is mounted to leg 42. In this manner material discharged through the gap between bucket portions 34 and 36 cannot pass between the end of screen 48 and the inside of upright legs 42.

Referring now to FIGS. 5 through 8, first preferred power drive means 66 for movement of the screening unit 49 between its operative and inoperative positions and for use on a two part bucket 26 as illustrated in FIGS. 1 and 2 is described in greater detail. The power drive comprises otherwise identical left and right hand portions which are mounted to bucket 26. Since the halves of the drive are otherwise identical only one, namely the left hand half, is illustrated in and described on hand of FIG. 5. It will be understood that each illustrated and described component of the drive means is duplicated on the other, right hand side of the bucket.

Pivot pin 38 is defined by an elongated shaft 68 extending through a pair of side-by-side journal bearings generally identified with the reference No. 70 and which are, respectively, secured to the forward and aft portions 36 and 34 of bucket 26. Hydraulic actuator 72 is mounted behind aft portion 34 and its actuation opens and closes the bucket portions. An outermost end 74 of shaft 68 projects some distance past journaled bearing 70. A hub 76 extends through an aperture 79 in leg 42 and is keyed to the outer shaft end with a pair of oppositely mounted keys 78 to rigidly secure screening unit 49 against rotation about and/or axial movement along shaft 68. The outer face of hub 76 is flush with the end of shaft 68. A lock bar 80 welded to hub 76 and extends across the face and the shaft end. A pair of bolts 82 are threaded into the shaft and secure the hub and the lock bar to the shaft. The lock bar is further secured to the upper end 54 of the leg with a second pair of bolts 84 threaded into the leg. The outer ends of the lock bar are disposed between opposing pairs of stop blocks 86 and 88 which prevent relative rotational movements between the frame leg and the lock bar. Thus, the lock bar and the keyed hub securely interconnect frame leg 42 and shaft 68 and transmit rotational movement of the shaft to screening unit 49. Additionally, the provision of a releasable hub enables the initial removal of the hub preparatory to disconnecting the screening unit from shaft 68. The oversized apertures 79 and the relative flexibility of frame leg 42 substantially facilitate such removal without the need for elaborate and time consuming disassembly of the screening unit.

On the inside, adjacent the center line of the bucket, shaft 68 mounts an end cap 90 which is also keyed onto the shaft and secured thereto by a pair of threaded bolts 92. A bearing plate 94 and a guide plate 96 are secured, e.g. welded to the back side of aft bucket portion 34 and include bores (not separately shown) aligned with the bores through journaled bearings 70 for the rotatable support of the inside ends of shaft 68.

A high strength bar 98 extends generally tangentially away from the periphery of end cap 90 and at its end mounts a pivot pin 100 that is radially spaced from the axis of shaft 6 8. A pawl 102 engages pin 100 and is pivotable thereabout. The pawl includesa circularly arcuate, concave surface 104' of a radius equal to or greater than the radius of the periphery of end cap 90 and which is positioned from pivot pin 100 so that the concave surface can rest against the periphery of the cap, as is illustrated in FIG. 8. The end of the pawl opposite the end connected to pivot pin defines a pair of spaced apart leaves 108 (see FIG. 5) which straddle the cross head of a ram 110 of a hydraulic actuator 112. A cross pin 114 pivotally connects the cross head and the pawl leaves.

Cross pin 114 extends beyond pawl leaves 108 into guide slots 118 defined by guide plate 96 disposed on one side of the pawl and a second guide plate 120 disposed opposite of the first plate on the other side of the pawl. The guide slots and the guide plates are parallel and determine the motion path of cross pin 114, the ram cross head and the pawl leaves. In this manner, the natural path of the cross pin can be altered as necessary to guide the cross head and the pawl away from other components that might be positioned in the vicinity of the pawl or the cross head to thereby prevent interferences and assure a free motion path for the cross head and the pawl. Additionally, the slots provide support for the cross pin to prevent it from wedging or cocking when the pin is guided along a motion path other than its natural path.

Hydraulic actuator 112 also includes a hydraulic cylinder 122 the lower end of which is pivotally connected to a pin 124 mounted to ends of first and second upwardly extending mounting bars 126 and 128 having their other ends secured, e.g. welded to guide plate 96 and the back side of aft bucket portion 34, respectively. A brace bar 130 is further connected to pin 124 to rigidly mount the pin and prevent it from moving under lateral forces.

Shaft 68 is keyed to leg hub 76 and end cap 90 so that when screening unit 49 is in its lowermost, operative position and ram 110 is in its fully extended position concave surface 104 of pawl 102 engages the periphery of the end cap and bar 98 points generally away from ram 110.

If shaft 68 is disposed closely adjacent the back side of aft bucket 34 bar 98 and pawl 102 may extend forward past aft portion 46 of the bucket. To accommodate the two the bucket includes a generally rectangularly shaped cutout 132 over which a trough shaped cover 134 is placed to protect the power drive from damage through contact with the materials disposed in the bucket.

Screening unit 49 is raised into its inoperative position by pressurizing the hydraulic actuator to retract ram 110 into cylinder 122. This causes movement of cross pin 114 along guide slots 118 in guide plates 96 and 120. Initially, force is applied to pawl 102 by the cross pin which is parallel to the axis of ram 110 and which causes an oppositely acting reaction force between arcuate pawl surface 104 and the periphery of end cap 90. A secondary reaction force acting in the opposite direction from the force applied to the pawl by the cross pin is created at the outer end of bar 98 and causes shaft 68 to rotate in a counterclockwise direction, as viewed in FIGS. 7 and 8, whereby the screening unit is rotated in a. counterclockwise direction toward its inoperative position.

Further retraction of the ram continues to rotate shaft 68 in the above described manner until the axisof pivot pin 100 moves past dead center, or past the straight line connecting the axes of cylinder mounting pin 124 and shaft 68. Thereafter, the continued retraction of ram 110 places pawl 102 in tension which continues to rotate shaft 68 until the ram is fully retracted. At that point, illustrated in FIG. 7, screening unit 49 is in its uppermost, inoperative position.

The provision of the pawl with its concavely arcuate surface 104 enables the translation of the rams linear movement into a rotational movement of shaft 68 through an angle of rotation of up to about 180 and more. Thus, the high power output of presently available hydraulic piston actuators, together with their relatively low price, which are presently difficult to duplicate with any other power drive mechanism, can be employed for rotating the screening unit even though such rotation requires the exertion of a sizeable torque due to the relatively great weight and physical size of the screening unit.

Although the power drive means for the vibratory screen illustrated in FIGS. through 8 is presently preferred for use with two part buckets, it can be replaced with suitable mechanical or electrical power actuators employing a gear and/or rack mechanisms (not shown) or the like for the translation of the linear motion into rotary shaft motion.

Referring now briefly to FIG. 11, in another preferred embodiment of the invention, the power drive for screening unit 49 comprises a high torque rotary hydraulic motor 136 which has an output shaft 138 that is directly coupled to upper end 54 of upright frame leg 42. Base 140 of the hydraulic motor is suitably mounted to the back side of aft bucket portion 34. Energization of the motor pivots the screening unit in one or the other direction from the operative to the inoperative position and vice versa. If insufficient torque is delivered by the outer shaft of the hydraulic motor a suitable torque multiplying gear arrangement (not separately shown) may be interposed between the motor and the U-shaped frame for pivotal movement of the latter about the former.

Referring to FIGS. 9 and 10, to prevent large objects such as heavy rocks and the like from dropping onto and damaging vibratory screen 48 when a two part bucket 26 having aft and forward portions 34 and 36, respectively, is used a large mesh bucket screen 142 is provided through which the material disposed in the bucket must pass before it can contact the vibratory screen. The bucket screen is constructed of a generally rectangular outer frame 144 and a plurality of trans verse bars 146 disposed parallel to the short sides of the frame and spaced a distance, such as 6 inches, to prevent rocks and the like having minimum dimension in excess thereof from dropping onto the vibratory screen. An aft side 148 of the bucket screen is disposed within aft bucket portion 34 and secured thereto by a pair of pivot pins 150 secured to side walls 152 of the aft bucket portion.

The bucket screen has sufficient width so that its forward side 154 rests against bottom plate 156 of forward bucket portion 36 when the bucket is opened to form a material discharge gap 158 between the two bucket halves. Upon closing of the bucket halves, the forward end of the bucket screen slides along bottom plate 156 until the bucket is closed. In use, excessively large and heavy rocks are thus prevented from dropping onto the vibratory screen thereby preventing possible damage thereto. The bucket screen is robust and virtually indestructible and articles screened out by it can be subsequently dumped at a suitable place.

If the maximum opening of the bucket exceeds the width of bucket screen 142 a pair of laterally spaced tension cables (not shown) are secured to forward side 154 of the screen, looped over pulleys (not shown) mounted on top of bucket aft portion 34 and connected to the boss pin housing of clam above hydraulic actuator 72 for the closing and opening of bucket 26. The forward end of the bucket screen remains thereby suspended even if the forward end slides off bottom plate 156 of the forward bucket portion. This enables the opening and closing of the bucket even beyond the reach of the bucket screen without dropping the screen 7 and jamming the bucket in an open position.

Referring to FIGS. 1 through 10, in use a hydraulic system (not shown) is provided to independently operate hydraulic actuators for arms 28, tilt mechanism 30, hydraulic actuators 72 to open and close bucket 26. Initially the unit is pivoted into its inoperative position and bucket 26 is tilted and lowered, as illustrated in FIG. 2, to pick up ground. When the bucket is full, it is lifted off ground, suitably tilted backwards and vibratory screen 48 is pivoted into its operative position. Vibrator 52 is energized to vibrate screen 48 and hydraulic ram 72 is actuated to discharge material in the bucket onto the screen. When the bucket is emptied and all material has been screened the bucket is closed and screening unit 49 is pivoted back into its inoperative position. Materials not passing the screen are thereby automatically discharged from the vibratory screen. A new load is now picked up with the bucket and the above described steps are repeated.

To prevent screening unit 49 from pivoting backwardly and downwardly towards the operators stand on vehicle 18, the operator will compensate backward tilting of bucket 26 by correspondingly pivoting the screening unit forwardly with respect to the bucket. Additionally, a suitable preferably spring loaded latching mechanism (not separately shown) which is hydraulically disengageable with screening unit actuators 112 is preferably provided to firmly retain the screen in its upwardly extending inoperative position.

WE CLAIM:

1. In an earth handling apparatus having a movable vehicle, bucket means movably mounted to the vehicle for the pickup and holding of a quantity of screenable material, and means for discharging the material from the bucket means, the improvement comprising: screen means for screening material discharged from the bucket means and separating relatively large items from material passing the screen, and means mounting the screen means to the bucket means and means for pivotally moving the screen means with respect to the bucket means over an arc of up to at least about for positioning the screen means beneath the bucket means to intercept material discharged from the bucket means and for positioning the screen means sufficiently above and clear of the bucket means to prevent obstruction of the bucket means by the screen means during use of the bucket means for the pickup of further screenable material.

2. Apparatus according to claim 1 wherein the screen mounting means includes a horizontally disposed shaft, and wherein the means for pivotally moving comprises a frame holding the screen means, a hydraulic actuator a radial member protruding from the shaft, a pawl pivotally connected to the radial member and the actuator, and further including means mounting the actuator with respect to the shaft so that upward movement of the screen means froman operative into an inoperative position requires the exertion of an actuator force baising a portion of the pawl intermediate the pivotal connections against the shaft to thereby impart a force to the member causing pivotal movement to the shaft and thus raise the screen means.

3. Apparatus for use with buckets holding and moving screenable material which are pivotable about a substantially horizontal axis for the loading and unloading of the bucket comprising: a generally U-shaped frame for mounting a screen and having upwardly extending arms laterally spaced for positioning of the arms adjacent sides of the bucket which are substantially perpendicular to a horizontal axis about which the bucket is pivotable, shaft means coaxial with the pivot axis, keyed to the arms adjacent an upper end thereof and mounting the frame for pivotal movement about the horizontal axis, the spacing between the horizontal axis and the screen being sufficient to prevent contact between the frame and the screen and the bucket when the frame pivots from a lowermost position in which the screen is beneath the bucket into an uppermost position in which the screen is above the bucket, means pivotally mounting the bucket to the shaft means, and power actuated means for rotating the shaft means to pivot the screen between the lower and upper positions.

4. Apparatus according to claim 3 wherein the screen comprises a vibratory screen substantially horizontally disposed between the arms for receipt of material dumped from the bucket, and including deflector means secured to sides of the arms facing the vibratory screen and guiding material dumped from the bucket into the screen.

5. Apparatus according to claim 3 wherein the power actuated means comprises a hydraulic cylinder portion pivotally secured to the bucket and a hydraulic ram portion pivotally secured to the shaft means, and including guide means secured to the bucket and in engagement with the ram portion for guidance of the ram portion over the length of its stroke to rotate the shaft means through an are substantially in excess of 90.

6. Apparatus for screening earth, rock and the like discharged from container means carried by a support structure comprising: a frame member, a screen mounted to the frame member, pivot means movably connecting the frame member and the support structure permitting placement of the screen beneath the container means in a substantially horizontal, operative position, and power driven means for pivoting the frame member with respect to the container means about a substantially horizontal axis defined by the pivot means into an inoperative position through an arc of substantially more than about 90 to provide clear access to the container means in a substantially horizontal direction to facilitate the filling of the container means and for discharging screened-out matter from the screen.

7. Earth moving and screening equipment comprising: a vehicle having elongated arm means pivotable about a horizontal axis for raising and lowering free ends of arm means, a bucket secured to the free end and pivotable about a horizontal axis for placement of the bucket into an earth pickupposition and an earth dumping position, means connected to the arm means and to the bucket for pivoting the bucket with respect to the arm means, a generally Urshaped frame having upwardly extending legs straddling the bucket, means pivotally securing upper ends of the legs to the bucket for pivotal movement of the frame about a substantially horizontal axis independent of said pivotal bucket movement between earth pickup and dumping positions, the frame including a substantially horizontally disposed base frame, the legs having a configuration so that the base frame can be positioned beneath the bucket and earth being dumped from the bucket falls past the base frame, a vibratory screen mounted to the base frame so that screened material can fall from the bucket through the screen, a hydraulic actuator connected to the bucket and the U-shaped frame for pivotally moving the frame from an operative position in which the screen is beneath the bucket into an inoperative position in which the screen is disposed above the bucket, and means for translating linear movements of the actuator into pivotal movements of the frame with respect to the bucket over an arc substantially in excess of 90, whereby the bucket can be used for earth pickup and discharge independent of and free of interference from the screen when the screen is in the inoperative position.

8. Equipment in accordance with claim 7 wherein the means for translating comprises a pawl pivotally connected to an actuator ram, and force transmission means for the transmission of tangentially acting forces to the pivotal securing means extending away from the pivotal securing means in a generally radial direction and pivotally connected to the pawl for translating a linear movement of the ram into a rotational movement of the pivotal securing means, the pawl and the transmission means being positioned so that forces exerted by the ram for the raising of the frame create a substantially radial reaction force in the pivotal securing means and a tangentially acting force in the transmission means when the ram is in one of its: limiting positions to enable the pivotal movement of the pivotal securing means through an arc of at least up to about 1 9. Equipment according to claim 8 including means connected to the bucket defining a motion path for the pivotal connection between the ram and the pawl.

10. Equipment according to claim 9 wherein the path defining means includes means defining a path other than the natural path of said pivotal connection.

11. Equipment according to claim 7 wherein the bucket comprises relatively pivotal forward and rear portions for discharge of the material by moving the portions away from each other to open a discharge gap therebetween, and wherein the equipment further includes a large mesh screen extending across the width of the bucket, means movably securing one end of the screen to one of the bucket portions, the bucket having a sufficient width to fully span across the gap when the portions are in their open positions to prevent large rocks and the like from being discharged onto the screen.

12. Apparatus for use with buckets for holding and moving screenable material, the buckets being pivotal about a substantially horizontal axis for the loading and unloading of the bucket, the apparatus comprising a generally Ueshaped frame for mounting a screen and having upwardly extending arms laterally spaced for positioning of the arms adjacent sides of the bucket which are substantially perpendicular to the horizontal axis about which the bucket is pivotable, shaft means engaging the arms adjacent an upper end thereof and mounting the frame for pivotal movement about a horizontal axis substantially parallel to said horizontal bucket pivot axis, the spacing between the frame pivot axis and the screen being sufficient to prevent contact between the frame and the screen and the bucket when the frame pivots from a lowermost position in which the screen is beneath the bucket into an uppermost position in which the screen is above the bucket, and power actuated means for pivotally moving the frame about the frame pivot axis between the lower and upper positions comprising a hydraulic motor having a power rotated shaft, and means ope'ratively connecting the motor to the bucket and frame for movement of the screen between the upper and the lower positions by actuation of the power rotated shaft. 

1. In an earth handling apparatus having a movable vehicle, bucket means movably mounted to the vehicle for the pickup and holding of a quantity of screenable material, and means for discharging the material from the bucket means, the improvement comprising: screen means for screening material discharged from the bucket means and separating relatively large items from material passing the screen, and means mounting the screen means to the bucket means and means for pivotally moving the screen means with respect to the bucket means over an arc of up to at least about 180* for positioning the screen means beneath the bucket means to intercept material discharged from the bucket means and for positioning the screen means sufficiently above and clear of the bucket means to prevent obstruction of the bucket means by the screen means during use of the bucket means for the pickup of further screenable material.
 2. Apparatus according to claim 1 wherein the screen mounting means includes a horizontally disposed shaft, and wherein the means for pivotally moving comprises a frame holding the screen means, a hydraulic acTuator a radial member protruding from the shaft, a pawl pivotally connected to the radial member and the actuator, and further including means mounting the actuator with respect to the shaft so that upward movement of the screen means from an operative into an inoperative position requires the exertion of an actuator force baising a portion of the pawl intermediate the pivotal connections against the shaft to thereby impart a force to the member causing pivotal movement to the shaft and thus raise the screen means.
 3. Apparatus for use with buckets holding and moving screenable material which are pivotable about a substantially horizontal axis for the loading and unloading of the bucket comprising: a generally U-shaped frame for mounting a screen and having upwardly extending arms laterally spaced for positioning of the arms adjacent sides of the bucket which are substantially perpendicular to a horizontal axis about which the bucket is pivotable, shaft means coaxial with the pivot axis, keyed to the arms adjacent an upper end thereof and mounting the frame for pivotal movement about the horizontal axis, the spacing between the horizontal axis and the screen being sufficient to prevent contact between the frame and the screen and the bucket when the frame pivots from a lowermost position in which the screen is beneath the bucket into an uppermost position in which the screen is above the bucket, means pivotally mounting the bucket to the shaft means, and power actuated means for rotating the shaft means to pivot the screen between the lower and upper positions.
 4. Apparatus according to claim 3 wherein the screen comprises a vibratory screen substantially horizontally disposed between the arms for receipt of material dumped from the bucket, and including deflector means secured to sides of the arms facing the vibratory screen and guiding material dumped from the bucket into the screen.
 5. Apparatus according to claim 3 wherein the power actuated means comprises a hydraulic cylinder portion pivotally secured to the bucket and a hydraulic ram portion pivotally secured to the shaft means, and including guide means secured to the bucket and in engagement with the ram portion for guidance of the ram portion over the length of its stroke to rotate the shaft means through an arc substantially in excess of 90*.
 6. Apparatus for screening earth, rock and the like discharged from container means carried by a support structure comprising: a frame member, a screen mounted to the frame member, pivot means movably connecting the frame member and the support structure permitting placement of the screen beneath the container means in a substantially horizontal, operative position, and power driven means for pivoting the frame member with respect to the container means about a substantially horizontal axis defined by the pivot means into an inoperative position through an arc of substantially more than about 90* to provide clear access to the container means in a substantially horizontal direction to facilitate the filling of the container means and for discharging screened-out matter from the screen.
 7. Earth moving and screening equipment comprising: a vehicle having elongated arm means pivotable about a horizontal axis for raising and lowering free ends of arm means, a bucket secured to the free end and pivotable about a horizontal axis for placement of the bucket into an earth pickup position and an earth dumping position, means connected to the arm means and to the bucket for pivoting the bucket with respect to the arm means, a generally U-shaped frame having upwardly extending legs straddling the bucket, means pivotally securing upper ends of the legs to the bucket for pivotal movement of the frame about a substantially horizontal axis independent of said pivotal bucket movement between earth pickup and dumping positions, the frame including a substantially horizontally disposed base frame, the legs having a configuration so that the base frame can be posiTioned beneath the bucket and earth being dumped from the bucket falls past the base frame, a vibratory screen mounted to the base frame so that screened material can fall from the bucket through the screen, a hydraulic actuator connected to the bucket and the U-shaped frame for pivotally moving the frame from an operative position in which the screen is beneath the bucket into an inoperative position in which the screen is disposed above the bucket, and means for translating linear movements of the actuator into pivotal movements of the frame with respect to the bucket over an arc substantially in excess of 90*, whereby the bucket can be used for earth pickup and discharge independent of and free of interference from the screen when the screen is in the inoperative position.
 8. Equipment in accordance with claim 7 wherein the means for translating comprises a pawl pivotally connected to an actuator ram, and force transmission means for the transmission of tangentially acting forces to the pivotal securing means extending away from the pivotal securing means in a generally radial direction and pivotally connected to the pawl for translating a linear movement of the ram into a rotational movement of the pivotal securing means, the pawl and the transmission means being positioned so that forces exerted by the ram for the raising of the frame create a substantially radial reaction force in the pivotal securing means and a tangentially acting force in the transmission means when the ram is in one of its limiting positions to enable the pivotal movement of the pivotal securing means through an arc of at least up to about 180*.
 9. Equipment according to claim 8 including means connected to the bucket defining a motion path for the pivotal connection between the ram and the pawl.
 10. Equipment according to claim 9 wherein the path defining means includes means defining a path other than the natural path of said pivotal connection.
 11. Equipment according to claim 7 wherein the bucket comprises relatively pivotal forward and rear portions for discharge of the material by moving the portions away from each other to open a discharge gap therebetween, and wherein the equipment further includes a large mesh screen extending across the width of the bucket, means movably securing one end of the screen to one of the bucket portions, the bucket having a sufficient width to fully span across the gap when the portions are in their open positions to prevent large rocks and the like from being discharged onto the screen.
 12. Apparatus for use with buckets for holding and moving screenable material, the buckets being pivotal about a substantially horizontal axis for the loading and unloading of the bucket, the apparatus comprising a generally U-shaped frame for mounting a screen and having upwardly extending arms laterally spaced for positioning of the arms adjacent sides of the bucket which are substantially perpendicular to the horizontal axis about which the bucket is pivotable, shaft means engaging the arms adjacent an upper end thereof and mounting the frame for pivotal movement about a horizontal axis substantially parallel to said horizontal bucket pivot axis, the spacing between the frame pivot axis and the screen being sufficient to prevent contact between the frame and the screen and the bucket when the frame pivots from a lowermost position in which the screen is beneath the bucket into an uppermost position in which the screen is above the bucket, and power actuated means for pivotally moving the frame about the frame pivot axis between the lower and upper positions comprising a hydraulic motor having a power rotated shaft, and means operatively connecting the motor to the bucket and frame for movement of the screen between the upper and the lower positions by actuation of the power rotated shaft. 